6,868 research outputs found

    High prevalence of Sarcocystis calchasi in racing pigeon flocks in Germany

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    The apicomplexan parasite Sarcocystis calchasi (Coccidia: Eimeriorina: Sarcocystidae) is the causative agent of Pigeon Protozoal Encephalitis (PPE) and infects birds of the orders Columbiformes, Piciformes and Psittaciformes. Accipiter hawks (Aves: Accipitriformes) are the definitive hosts of this parasite. Infections of S. calchasi have been detected in Germany, the United States and Japan. However, the prevalence of the parasite in racing pigeon flocks has not yet been determined. Here, the first cross-sectional prevalence study to investigate S. calchasi in pigeon racing flocks was accomplished including 245 pigeon flocks across Germany. A total of 1,225 muscle biopsies, were taken between 2012 and 2016 and examined by semi-nested PCR for S. calchasi DNA targeting the ITS gene. Additionally, a questionnaire on construction of the aviary as well as management and health status of the flock was conducted. In 27.8% (95% C.I. = 22.3–33.8%) of the flocks, S. calchasi DNA was detected in at least one pigeon. Positive flocks were located in 15 out of 16 federal states. A significant increase of infected racing pigeons was seen in spring. Half-covered or open aviary constructions showed a trend of increase of the prevalence rate, while anti-coccidian treatment and acidified drinking water had no effects. The high prevalence and the geographical distribution of S. calchasi suggest a long-standing occurrence of the parasite in the German racing pigeon population. For pigeons presented with neurological signs or other symptoms possibly related to PPE, S. calchasi should be considered as a potential cause throughout Germany

    Kato square root problem with unbounded leading coefficients

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    We prove the Kato conjecture for elliptic operators, L=−∇⋅((A+D)∇ )L=-\nabla\cdot\left((\mathbf A+\mathbf D)\nabla\ \right), with A\mathbf A a complex measurable bounded coercive matrix and D\mathbf D a measurable real-valued skew-symmetric matrix in Rn\mathbb{R}^n with entries in BMO(Rn)BMO(\mathbb{R}^n);\, i.e., the domain of L \sqrt{L}\, is the Sobolev space H˙1(Rn)\dot H^1(\mathbb{R}^n) in any dimension, with the estimate ∥L f∥2≲∥∇f∥2\|\sqrt{L}\, f\|_2\lesssim \| \nabla f\|_2

    Assessing the Market for Poultry Litter in Georgia: Are Subsidies Needed to Protect Water Quality?

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    Concerns about nutrient loads into our waters have focused attention on poultry litter applications. Like many states with a large poultry industry, Georgia recently designed a subsidy program to facilitate the transportation of poultry litter out of vulnerable watersheds. This paper uses a transportation model to examine the necessity of a poultry litter subsidy to achieve water protection goals in Georgia. We also demonstrate the relationship between diesel and synthetic fertilizer prices and the value of poultry litter. Results suggest that a well functioning market would be able to remove excess litter from vulnerable watersheds in the absence of a subsidy.fertilizer, phosphorous, poultry litter, subsidy, transportation model, water quality, Environmental Economics and Policy, Marketing, Q12, Q13, Q25, Q53,

    Distribution and Population Characteristics of Lower Walleye in the Eleven Point River, Arkansas

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    Walleye Sander vitreus (Mitchill) distributions and ecology have been poorly studied in southern river basins. We studied the longitudinal distribution and population characteristics of walleye in an unregulated river within the Ozark region of the U.S., the lower Eleven Point River, Arkansas, which has high species diversity. Walleye were collected in a 60 km segment of the river by daytime boat electrofishing over a three year period (2002-2004). Catch rates, growth rates and size structure were high relative to other streams studied in North America. Catch per effort ( = 5.2/h) was similar seasonally, spatially and among years. Proportional stock structures were quite high ( = 80), with numerous fish collected over 600 mm total length, 4 kg in mass and greater than 10 years of age. Relative weights of all length groups (stock size, proportional size structure, relative size structure) were at or greater than 90. Stomach contents of walleye were more suggestive of a generalist strategy in a stream of high species diversity, as compared to the targeting of a single numerically dominant prey, which is common in lentic systems

    Vaccines to Combat Smoking

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    Background—Current U.S. FDA approved biological therapies for treating smoking target central nervous system processes. Although these therapies have had some success, relapse within a year is still high. Clearly additional strategies are needed to aid individuals in maintaining abstinence. Objective & Methods—We briefly discuss promising research using vaccines to combat smoking and then identify some potentially important directions for future research. Results & Conclusions—Immunization with a nicotine vaccine generates drug-specific antibodies that sequester some of the nicotine in peripheral circulation preventing it from entering the brain thus decreasing its addictive effects. Albeit promising, much more research is necessary to identify more efficacious vaccine designs and formulations, as well as optimal immunization regimens. A further understanding of the contributing factors to the substantial individual differences in immunogenicity to these vaccines and how to best use vaccines in combination with other treatment strategies will increase the success of intervention efforts

    Vaccines to Combat Smoking

    Get PDF
    Background—Current U.S. FDA approved biological therapies for treating smoking target central nervous system processes. Although these therapies have had some success, relapse within a year is still high. Clearly additional strategies are needed to aid individuals in maintaining abstinence. Objective & Methods—We briefly discuss promising research using vaccines to combat smoking and then identify some potentially important directions for future research. Results & Conclusions—Immunization with a nicotine vaccine generates drug-specific antibodies that sequester some of the nicotine in peripheral circulation preventing it from entering the brain thus decreasing its addictive effects. Albeit promising, much more research is necessary to identify more efficacious vaccine designs and formulations, as well as optimal immunization regimens. A further understanding of the contributing factors to the substantial individual differences in immunogenicity to these vaccines and how to best use vaccines in combination with other treatment strategies will increase the success of intervention efforts

    The Quasinormal Mode Spectrum of a Kerr Black Hole in the Eikonal Limit

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    It is well established that the response of a black hole to a generic perturbation is characterized by a spectrum of damped resonances, called quasinormal modes; and that, in the limit of large angular momentum (l≫1l \gg 1), the quasinormal mode frequency spectrum is related to the properties of unstable null orbits. In this paper we develop an expansion method to explore the link. We obtain new closed-form approximations for the lightly-damped part of the spectrum in the large-ll regime. We confirm that, at leading order in ll, the resonance frequency is linked to the orbital frequency, and the resonance damping to the Lyapunov exponent, of the relevant null orbit. We go somewhat further than previous studies to establish (i) a spin-dependent correction to the frequency at order 1/l1 / l for equatorial (m=±lm = \pm l) modes, and (ii) a new result for polar modes (m=0m = 0). We validate the approach by testing the closed-form approximations against frequencies obtained numerically with Leaver's method.Comment: 18 pages, 3 tables, 3 figure

    Development of Dynamic Local Work Load Measurement Method Using Electromyography (EMG) (an Experimental Measurement with Drilling Activities)

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    This paper presents a scheme to build a system of musculosceletal maesurement using Electromyography and for measuring physical dynamic workload of local muscles, i.e., drilling activities. Electro-myography (EMG) can be signal of muscle contractions and provides continous record as the analog signal. The result of this dynamic local workload measurement show a nonlinear relationship between peak level power spectra of EMG signal and torque. the work load for drilling 0.8 mm to 5 mm plate activities ranges between 0,1513 to 1, 6979 Joule

    Cerebellum Transcriptome of Mice Bred for High Voluntary Activity Offers Insights into Locomotor Control and Reward-Dependent Behaviors.

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    The role of the cerebellum in motivation and addictive behaviors is less understood than that in control and coordination of movements. High running can be a self-rewarding behavior exhibiting addictive properties. Changes in the cerebellum transcriptional networks of mice from a line selectively bred for High voluntary running (H) were profiled relative to an unselected Control (C) line. The environmental modulation of these changes was assessed both in activity environments corresponding to 7 days of Free (F) access to running wheel and to Blocked (B) access on day 7. Overall, 457 genes exhibited a significant (FDR-adjusted P-value < 0.05) genotype-by-environment interaction effect, indicating that activity genotype differences in gene expression depend on environmental access to running. Among these genes, network analysis highlighted 6 genes (Nrgn, Drd2, Rxrg, Gda, Adora2a, and Rab40b) connected by their products that displayed opposite expression patterns in the activity genotype contrast within the B and F environments. The comparison of network expression topologies suggests that selection for high voluntary running is linked to a predominant dysregulation of hub genes in the F environment that enables running whereas a dysregulation of ancillary genes is favored in the B environment that blocks running. Genes associated with locomotor regulation, signaling pathways, reward-processing, goal-focused, and reward-dependent behaviors exhibited significant genotype-by-environment interaction (e.g. Pak6, Adora2a, Drd2, and Arhgap8). Neuropeptide genes including Adcyap1, Cck, Sst, Vgf, Npy, Nts, Penk, and Tac2 and related receptor genes also exhibited significant genotype-by-environment interaction. The majority of the 183 differentially expressed genes between activity genotypes (e.g. Drd1) were under-expressed in C relative to H genotypes and were also under-expressed in B relative to F environments. Our findings indicate that the high voluntary running mouse line studied is a helpful model for understanding the molecular mechanisms in the cerebellum that influence locomotor control and reward-dependent behaviors
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